There has been great interest in identifying novel methods of preparing nano- and micro-electromechanical devices.
Micro-electromechanical systems (MEMS) devices comprise components between about 1 to 100 μm in size (i.e., 0.001 to 0.1 mm), and MEMS devices generally range in size from 20 μm to 1.0 mm. Such devices may be prepared using modified semiconductor device fabrication technologies, which are commonly used to make electronics. Patterning of the device is usually achieved using techniques such as lithography, photolithography, etching processes (e.g., wet etching using for example potassium hydroxide, tetramethylammonium hydroxide, or hydrogen fluoride; dry etching using for example vapor etching with xenon difluoride or hydrogen fluoride, or plasma etching), electrodischarge machining, and other technologies capable of manufacturing small devices.
Nano-electromechanical systems (NEMS) devices comprise components that have at least one dimension less than about 1 μm in size. Many of these devices have been carbon based, specifically diamond, carbon nanotubes and graphene. Key problems preventing the commercial application of nano-electromechanical devices have included low-yields and high device quality variability.
Atomic layer deposition (ALD) uses automated cycling of component gases to deposit solid materials conformally on solid surfaces. The growth of individual layers is a self-limiting reaction, resulting in linear growth of material, which is dependent upon the number of cycles to which a substrate is exposed. ALD allows thickness control and conformality unmatched by any other available industrial process. Moreover, ALD processes generally employ low temperatures, with typical deposition temperatures below 200° C. ALD materials currently available include ceramics (Al2O3, TaN, SiO2, HfO2, MgO, MnO), metals (W, Pt, Ru), semiconductors (ZnO, AlN), and various other inorganic materials. In the case where ALD processes generate amorphous polymer structures through sequential reactions that include organic molecules, this process is called molecular layer deposition (MLD), and allows controlled conformal deposition of an additional range of materials.
There is a need in the art for novel methods of preparing nano- and micro-electromechanical devices with specific structures. In one aspect, such methods should be reliable and allow for the preparation of devices with predetermined patterns. The present invention meets this need.